The present invention provides a novel router guide assembly which is capable of cutting quarter circles and fabricating grained annular pieces from a workpiece. The assembly is particularly suitable for rounding the corners of tabletops and forming quarter round molding.
Router machines have become a common wood-working tool used by professional cabinetmaker shops and furniture manufacturers. The movable powered router is a powerful tool capable of making edges of precise and decorative designs, as well as grooves.
Router machines are often used to cut quarter circles or fabricate quarter round molding. Assuring that each cut or molding is satisfactory requires skill and tedious preparation. To avoid errors even skilled craftsmen have found it necessary to make a template prior to cutting with a router. However, the making of a template is a tedious and costly procedure. In order to avoid the making of templates others have designed template attachments for making arcuate grooves and router guides.
One such template attachment is set forth in U.S. Pat. No. 3,716,085 (Wing), issued Feb. 13, 1973. The Wing patent discloses a router template attachment used in conjunction with a known type of router template for the purpose of providing the capability of routing arcuate pattern portions. However, this template attachment does not overcome the obstacles associated with having to prepare the template itself.
The present inventor has found it more desirable to use a router guide in place of a template attachment. Router guides have been used in the woodworking industry for many years. In particular, they have been designed to cut horizontal, vertical and arcuate patterns in cabinet doors. Various router guides are set forth in the following U.S. Pat. Nos.: 4,185,671 (Cotton), issued Jan. 29, 1980; 4,603,657 (Obradovich), issued Dec. 23, 1986; 3,841,368 (Ritter), issued Oct. 15, 1974; and 4,306,598 (Peot), issued Dec. 22, 1981.
Unfortunately, none of the aforementioned router guide devices are capable of cutting quarter circles or quarter round molding from a workpiece. U.S. Pat. No. 4,185,671 (Cotton) provides a router guide which is capable of routing arcuate designs in cabinet doors.
in the Cotton patent a router is mounted on the end of a bar which extends over the cabinet door or other panel to be routed and in which the router can be moved in any direction in a plane parallel to the panel by reason of the bar being mounted in a carrier for longitudinal movement in one dimension of the panel and the carrier being mounted for movement parallel to the other dimension of the panel. Making arcuate cuts requires the use of a radius arm which may be adjustably connected at one end to the bar and is slidably mounted in a pivot block mounted for movement in the same direction as the carriage. An adjustable stop on the radius arm limits its longitudinal movement and an adjustable stop limits movement of the pivot block whereby the router can be guided in a pre-selected curved path by causing the radius arm to pivot around the pivot block.
The router guide device disclosed in Cotton makes use of a very complicated and expensive guide apparatus, i.e., the radius arm and pivot block. Moreover, it provides a guide which is only capable of cutting slightly curved patterns and is unsuitable for use in the cutting of quarter circles or quarter round molding.
The present invention overcomes the deficiencies of the conventional router guides, since it is capable of cutting quarter circles and quarter round molding from a workpiece without the aid of templates. It is also very inexpensive to manufacture and relatively easy to install and adjust on pending workpieces. Furthermore, the present invention permits the cutting of workpieces to an angle of 90 degrees which is particularly suitable in the manufacture of tabletops and molding. Moreover, it enables adjustment of the radius involved in the cutting of quarter circles over a very wide range from one-half inch to eight inches in accordance with one embodiment.
Additional advantages of the present invention shall become apparent as described below.